#
State Selective Electron Capture in the Collision of S^{3+} Ions in Atomic Hydrogen and Helium

^{1}

^{2}

^{*}

## Abstract

**:**

^{3+}ions in collision with atomic hydrogen. The present paper completes a previous letter [9] and displays the full results concerning this process in order to provide a detailed understanding of the mechanism. These calculations show evidence of the predominance of the S

^{2+}(3s

^{2}3p3d)

^{3}F° capture level, already pointed out by translational energy spectroscopy experiments and confirms experimental measurements. A compared study of the behaviour of the S

^{3+}projectile colliding both hydrogen and helium targets is also presented.

## Introduction

^{3+}ions in H, H

_{2}and He at impact energies within the range 2.4-9.0 keV. They show evidence of an S

^{2+}triplet state, identified as the S

^{2+}(3s

^{2}3p3d)

^{3}F° level, lying 15.03 eV above the S

^{2+}ground state in agreement with atomic data [13], which appears to be the dominant capture state in the S

^{3+}+ H collision system over the entire range of impact energies investigated. The multichannel Landau-Zener approach fails to reproduce the experimental spectra, in particular it largely underestimates the capture on peak A assigned to the S

^{2+}(

^{3}F°) + H

^{+}level. We present here a full detailed study of the S

^{3+}(3s

^{2}3p) + H electron capture mechanism, including all the triplet and singlet states correlated to the

^{1,3}Σ and

^{1,3}Π entry channels and involved in the process by means of radial or rotational coupling matrix elements. The calculation has been performed for the ground state S

^{3+}(3s

^{2}3p)

^{2}P° + H entry channel only ; the metastable ion S

^{3+}(3s3p

^{2})

^{4}P evidenced in the ion beam, has not been taken into account in this study. These results may be compared to our previous work on the S

^{3+}+ He charge transfer process [8] using the CIPSI algorithm for the molecular treatment followed by a semi-classical collision dynamics.

## Molecular calculations of the S^{3+}(3s^{2}3p)^{2}P° + H collisional system

#### A. Potential energy curves

**Table I.**Comparison of atomic energy levels with experiment [17] (in eV).

MRCI calculation | Experiment | |
---|---|---|

S^{3+}(3s^{2}3p)^{2}P° | 35.11 | 34.98 |

S^{2+}(3s3p^{3})^{3}S° + H^{+} | 17.05 | |

S^{2+}(3s3p^{3})^{3}P° + H^{+} | 12.31 | 12.17 |

S^{2+}(3s3p^{3})^{3}D° + H^{+} | 10.34 | 10.35 |

S^{2+}(3s^{2}3p^{2})^{3}P + H^{+} | 0.0 | 0.0 |

^{2+}(3s

^{2}3p3d)

^{3}P° electron capture level cannot account for the present charge transfer mechanism. Effectively, the asymptotic energy difference between the entry channel

^{1,3}Π,

^{1,3}Σ

^{+}{S

^{3+}(3s

^{2}3p)

^{2}P° + H(1s)

^{2}S} and the capture levels correlated to the {S

^{2+}(3s

^{2}3p3d)

^{3}P° + H

^{+1}S} configuration is shown in tables to be equal to 3.65 eV, quite different from the energy defect of 6.2 eV observed experimentally for peak A. From the asymptotical repulsion term, this energy difference would lead to a long range interaction with an avoided crossing around R=15 a.u. which could hardly explain an important population of the corresponding capture channel. It seems thus likely, as proposed by Wilson et al. [6], to consider the capture level S

^{2+}(3s

^{2}3p3d)

^{3}F°, accessible from the entry channel

^{1,3}Π,

^{1,3}Σ

^{+}{S

^{3+}(3s

^{2}3p)

^{2}P° + H(1s)

^{2}S}. The collisional system appears thus relatively complex, and a great number of states have to be taken into account in both the triplet and singlet manifold including one-electron capture processes as well as reactions of capture and excitation of the 3s electron:

S^{3+}(3s^{2}3p)^{2}P° + H(1s)^{2}S | ^{3}Π, ^{3}Σ^{+} | ^{1}Π, ^{1}Σ^{+} | entry channel |

S^{2+}(3s3p^{3})^{1}P° + H^{+1}S | ^{1}Π, ^{1}Σ^{+} | ||

S^{2+}(3s3p^{3})^{3}S° + H^{+1}S | ^{3}Σ^{-} | ||

S^{2+}(3s^{2}3p3d)^{3}F° + H^{+1}S | ^{3}Φ, ^{3}Π, ^{3}Δ, ^{3}Σ^{+} | ||

S^{2+}(3s3p^{3})^{1}D° + H^{+1}S | ^{1}Π, ^{1}Δ, ^{1}Σ^{-} | ||

S^{2+}(3s3p^{3})^{3}P° + H^{+1}S | ^{3}Π, ^{3}Σ^{+} | ||

S^{2+}(3s3p^{3})^{3}D° + H^{+1}S | ^{3}Π, ^{3}Δ, ^{3}Σ^{-} | ||

S^{2+}(3s^{2}3p^{2})^{1}S + H^{+1}S | ^{1}Σ^{+} | ||

S^{2+}(3s^{2}3p^{2})^{1}D + H^{+1}S | ^{1}Π, ^{1}Δ, ^{1}Σ^{+} | ||

S^{2+}(3s^{2}3p^{2})^{3}P + H^{+1}S | ^{3}Π, ^{3}Σ^{-} |

^{3+}(3s

^{2}3p)

^{2}P° + H entry channel are displayed in Figures 1a,b for singlet states, and in Figure 2a,b for triplet ones. The Σ

^{-}levels have not been taken into account.

**Figures 1a,b.**Adiabatic potential energy curves of the

^{1}Σ

^{+},

^{1}Δ and

^{1}Π states of the S

^{3+}(3s

^{2}3p) + H collisional system.

^{1}Σ

^{+}states;

^{1}Δ states;

^{1}Π states. 1,

^{1}Σ

^{+},

^{1}Δ and

^{1}Π states corresponding to {S

^{2+}(3s

^{2}3p

^{2})

^{1}D + H

^{+1}S}; 2,

^{1}Σ

^{+}state corresponding to {S

^{2+}(3s

^{2}3p

^{2})

^{1}S + H

^{+1}S}; 3,

^{1}Δ and

^{1}Π states corresponding to {S

^{2+}(3s3p

^{3})

^{1}D° + H

^{+1}S}; 4,

^{1}Σ

^{+}and

^{1}Π states corresponding to {S

^{2+}(3s3p

^{3})

^{1}P° + H

^{+1}S}; 5,

^{1}Σ

^{+}and

^{1}Π states corresponding to {S

^{3+}(3s

^{2}3p)

^{2}P° + H(1s)

^{2}S}, entry channel.

^{1}Π and

^{1}Σ

^{+}entry channels and the corresponding capture levels of the {S

^{2+}(3s3p

^{3})

^{1}P° + H

^{+1}S} configuration. This crossing is associated with an energy defect of about 4.0 eV and cannot be attributed to any experimental peak, in fact such a long range crossing might be considered as almost inactive in the charge transfer mechanism. However, an efficient avoided crossing may be considered near R=7 a.u. corresponding to the interaction with the

^{1}Π {S

^{2+}(3s3p

^{3})

^{1}D° + H

^{+1}S} level, it corresponds to an energy defect of 8.2 eV and may contribute to the experimental peak B.

^{3}Π,

^{3}Σ

^{+}levels corresponding to the {S

^{2+}(3s3p

^{3})

^{3}P° + H

^{+1}S} configuration, around R=6 a.u.; they are associated with an energy defect of 9.19 eV and may contribute to the experimental peak B. Another interaction appears with the

^{3}Π {S

^{2+}(3s3p

^{3})

^{3}D° + H

^{+1}S} level, around R=5 a.u., which may contribute to peak C, with an energy defect of 11.16 eV. But the most important feature appears for the state quoted 4 in Fig. 2a,b which exhibits an avoided crossing around R=9.7 a.u., corresponding to an energy defect of 5.6 eV, with the entry channel in both

^{3}Σ

^{+}and

^{3}Π symmetries. This channel is associated simultaneously with state symmetry

^{3}Σ

^{+},

^{3}Δ,

^{3}Π, and

^{3}Φ and may thus be attributed without any ambiguity to the {S

^{2+}(3s

^{2}3p3d)

^{3}F° + H

^{+1}S} configuration, confirming the experimental deduction of Wilson et al. [6]. The energy defect appears however slightly lower than evidenced for the experimental peak A. From our ab-initio MRCI calculations, the S

^{2+}(

^{3}F°) capture level appears at an energy of 15.8 eV above the S

^{2+}(3s

^{2}3p

^{2})

^{3}P ground state, a somewhat higher value than the 15.03 eV experimental value of Wilson et al. [6] and the 15.8 eV value given by the NIST Database [13], although the set of molecular calculations appears to be globally in good accordance with the tabulated energies as shown in Table II.

**Table II.**Comparison with experiment [17] for asymptotic energy levels (in a.u.)

MRCI calculation | Experiment | |
---|---|---|

S^{3+}(3s^{2}3p)^{2}P° + H(1s)^{2}S | 0.0 | 0.0 |

S^{2+}(3s3p^{3})^{3}S° + H^{+} | -0.1572 | |

S^{2+}(3s3p^{3})^{1}P° + H^{+} | -0.1477 | -0.1628 |

S^{2+}(3s3p3d)^{3}F° + H^{+} | -0.2063 | -0.2313^{a} |

S^{2+}(3s3p^{3})^{1}D° + H^{+} | -0.3019 | -0.3117 |

S^{2+}(3s3p^{3})^{3}P° + H^{+} | -0.3379 | -0.3363 |

S^{2+}(3s3p^{3})^{3}D° + H^{+} | -0.4105 | -0.4032 |

S^{2+}(3s^{2}3p^{2})^{1}S + H^{+} | -0.6601 | -0.6625 |

S^{2+}(3s^{2}3p^{2})^{1}D + H^{+} | -0.7371 | -0.7347 |

S^{2+}(3s^{2}3p^{2})^{3}P + H^{+} | -0.7905 | -0.7837 |

^{a}ref. [6]

**Figures 2a,b.**Adiabatic potential energy curves of the

^{3}Σ

^{+},

^{3}Δ,

^{3}Π and

^{3}Φ states of the S

^{3+}(3s

^{2}3p) + H collisional system.

^{3}Σ

^{+}states;

^{3}Δ states;

^{3}Π states; Φ state. 1,

^{3}Π state corresponding to {S

^{2+}(3s

^{2}3p

^{2})

^{3}P + H

^{+1}S}; 2,

^{3}Δ and

^{3}Π states corresponding to {S

^{2+}(3s3p

^{3})

^{3}D° + H

^{+1}S}; 3,

^{3}Σ

^{+}and

^{3}Π states corresponding to {S

^{2+}(3s3p

^{3})

^{3}P° + H

^{+1}S}; 4,

^{3}Σ

^{+},

^{3}Δ,

^{3}Π and

^{3}Φ states corresponding to {S

^{2+}(3s

^{2}3p3d)

^{3}F° + H

^{+1}S}; 5,

^{3}Σ

^{+}and

^{3}Π states corresponding to {S

^{3+}(3s

^{2}3p)

^{2}P° + H(1s)

^{2}S}, entry channel.

#### B. Radial and rotational coupling matrix elements

**Figure 3.**Radial coupling matrix elements between

^{1}Π states of the S

^{3+}(3s

^{2}3p) + H collisional system (see labels in Figures 1a,b).

^{1}Σ

^{+}and

^{1}Δ states remain small for all distances, lower than 0.2 a.u., in relation with the smooth interactions observed between the corresponding potentials. The only sharp peak is observed between

^{1}Π states, around R=7 a.u and about 1.25 a.u. high, in correspondence with the avoided crossing between the

^{1}Π entry channel and the

^{1}Π {S

^{2+}(3s3p

^{3})

^{1}D° + H

^{+1}S} capture channel.

^{3}Σ

^{+}states show two peaks, one around R=6 a.u. corresponding to the avoided crossing between the entry channel and the

^{3}Σ

^{+}{S

^{2+}(3s3p

^{3})

^{3}P° + H

^{+1}S} capture level associated with the experimental peak B, and a sharper one, around R=9.7 a.u., in correspondence with the strong avoided crossing between the entry channel and the

^{3}Σ

^{+}{S

^{2+}(3s

^{2}3p3d)

^{3}F° + H

^{+1}S} excited one-electron capture level. This radial coupling matrix element reaches 2.75 a.u. and is clearly the most important one for the charge transfer process, associated with the experimental peak A. Radial coupling between

^{3}Δ states remain small for all internuclear distances. The

^{3}Π levels show also such a sharp peak for the radial coupling corresponding to the avoided crossing with the

^{3}Π {S

^{2+}(3s

^{2}3p3d)

^{3}F° + H

^{+1}S} capture channel. It reaches even 3.5 a.u. and is markedly higher that the other radial coupling matrix elements. The coupling associated with the avoided crossing between the

^{3}Π entry channel and the

^{3}Π{S

^{2+}(3s3p

^{3})

^{3}P° + H

^{+1}S} level presents a peak, 2.5 a.u. high, around R=6 a.u. and the interaction with the

^{3}Π {S

^{2+}(3s3p

^{3})

^{3}D° + H

^{+1}S} capture channel shows a smooth variation of the radial coupling matrix element with a hump around R=5 a.u..

**Figures 4a,b.**Radial coupling matrix elements between

^{3}Σ

^{+},

^{3}Δ and

^{3}Π states of the S

^{3+}(3s

^{2}3p) + H collisional system (see labels in Figures 2a,b).

^{3}Σ

^{+}{S

^{3+}(3s3p

^{3})

^{3}P° + H

^{+1}S} and

^{3}Π{S

^{2+}(3s3p

^{3})

^{3}D° + H

^{+1}S} levels. The couplings corresponding to the same configuration reach the asymptotical value 1.0 a.u., as shown for the

^{3}Σ

^{+}-

^{3}Π couplings corresponding to the {S

^{3+}(3s

^{2}3p)

^{2}P° + H(1s)

^{2}S} and the {S

^{2+}(3s3p

^{3})

^{3}P + H

^{+1}S} configurations, as well as to the

^{3}Π-

^{3}Δ rotational couplings associated with the {S

^{2+}(3s3p

^{3})

^{3}D° + H

^{+1}S} configuration. For the {S

^{2+}(3s

^{2}3p3d)

^{3}F° + H

^{+1}S} capture channel, both

^{3}Σ

^{+}and

^{3}Δ states contribute to the rotational coupling with the

^{3}Π level, giving a double value for the matrix element. In correspondence with the crossing between this S

^{2+}(3s

^{2}3p3d)

^{3}F° capture level and the entry channel, an abrupt decrease may be observed for this rotational coupling to reach the value around 1.0 a.u. corresponding to the 5

^{3}Σ-5

^{3}Π coupling of the entry channel, and inversely.

**Figure 5.**Rotational coupling matrix elements between

^{3}Σ

^{+}-

^{3}Π and

^{3}Π-

^{3}Δ states of the S

^{3+}(3s

^{2}3p) + H collisional system (see labels in Fig. 2a,b).

^{______}4

^{3}Σ + 4

^{3}Δ/ 4

^{3}Π; 5

^{3}Σ / 5

^{3}Π; 3

^{3}Σ / 3

^{3}Π; 2

^{3}Δ / 2

^{3}Π; 3

^{3}Σ / 2

^{3}Π

#### C. Collision dynamics

^{1,3}Σ

^{+}and

^{1,3}Π entry channels. The translation effects may be taken into account in the frame of the common translation factor approximation developed by Errea et al. [19] which introduces a correction over the radial and rotational coupling matrix elements determined from the quadrupole moment tensor. The radial and rotational coupling matrix elements may indeed be transformed respectively into $\langle {\Psi}_{K}|\partial /\partial R-({\epsilon}_{K}-{\epsilon}_{L}){z}^{2}/2R|{\Psi}_{L}\rangle $ and $\langle {\Psi}_{K}|i{L}_{y}+({\epsilon}_{K}-{\epsilon}_{L})zx|{\Psi}_{L}\rangle $ where ε

_{K}and ε

_{L}are the electronic energies of states ψ

_{K}and ψ

_{L}, and z

^{2}and zx are the components of the quadrupole moment tensor. The sulfur nucleus has been taken as origin of the electronic coordinates.

**Table III.**Partial cross sections on the exit channels in the S

^{3+}(3s

^{2}3p)

^{2}P° + H process (in 10

^{-16}cm

^{2}).

E_{lab} (keV) | 2.00 | 2.88 | 3.92 | 5.12 | 6.49 | 8.01 |
---|---|---|---|---|---|---|

S^{2+}(3s3p^{3})^{1}P° | 0.06 | 0.79 | 0.63 | 0.73 | 0.73 | 0.87 |

S^{2+}(3s^{2}3p3d)^{3}F° | 17.63 | 16.29 | 14.57 | 13.54 | 13.08 | 11.85 |

σ_{A} | ||||||

S^{2+}(3s3p^{3})^{1}D° | 0.02 | 0.03 | 0.05 | 0.12 | 0.23 | 0.31 |

σ^{1}_{B} | ||||||

S^{2+}(3s3p^{3})^{3}P° | 9.49 | 11.90 | 12.19 | 10.54 | 9.52 | 8.37 |

σ^{2}_{B} | ||||||

S^{2+}(3s3p^{3})^{3}D° | 6.40 | 6.85 | 8.08 | 7.78 | 7.87 | 7.63 |

σ_{C} | ||||||

S^{2+}(3s^{2}3p^{2})^{3}P | 0.0001 | 0.0004 | 0.0006 | 0.0016 | 0.0018 | 0.0036 |

σ_{A}/σ_{B} | 1.85 | 1.36 | 1.19 | 1.27 | 1.34 | 1.36 |

σ_{B}/σ_{C} | 1.48 | 1.74 | 1.51 | 1.37 | 1.24 | 1.14 |

^{2+}(3s

^{2}3p3d)

^{3}F° capture channel attributed to peak A is clearly the dominant charge transfer channel. With regard to the energy defect, two exit channels may contribute to the experimental peak B and σ

_{B}=σ

^{1}

_{B}+σ

^{2}

_{B}with a dominant contribution σ

^{2}

_{B}of the S

^{2+}(3s3p

^{3})

^{3}P° capture level, this leads to a ratio σ

_{A}/σ

_{B}for the partial cross sections between peak A and peak B mainly around 1.3 as observed on the experimental spectra.

**Figure 6.**Calculated cross-sections on peak A, B, C (in 10

^{-16}cm

^{2}) and comparison with experimental data [6]. ${\mathrm{X}}$ (experiment)/${\dots \dots \dots}$ (calculation), σ

_{A}/σ

_{B}; ${\mathrm{X}}$ (experiment)/${\dots \dots \dots}$ (calculation), σ

_{B}/σ

_{C}.

^{2+}(3s3p

^{3})

^{3}D° exit channel is slightly underestimated and remains always lower than peak B, nevertheless it increases at higher energies and reaches the same order of magnitude as peak B as observed experimentally. The partial cross sections on the S

^{2+}(3s3p

^{3})

^{1}P° channel increases also with energy but remains much lower. The cross sections towards the S

^{2+}(3s

^{2}3p

^{2})

^{1}S and S

^{2+}(3s

^{2}3p

^{2})

^{1}D exit channels are almost zero for all collision energies, and the cross sections on the S

^{2+}(3s

^{2}3p

^{2})

^{3}P capture channel remain negligible.

## Comparison with the S^{3+}(3s^{2}3p)^{2}P + He collisional system

^{3+}(3s

^{2}3p)

^{2}P + He entry channel:

S^{3+}(3s^{2}3p)^{2}P + He(1s^{2})^{1}S | ^{2}Σ^{+}, ^{2}Π | entry channel |

S^{2+}(3s^{2}3p^{2})^{1}S + He^{+}(1s)^{2}S | ^{2}Σ^{+} | |

S^{2+}(3s^{2}3p^{2})^{1}D + He^{+}(1s)^{2}S | ^{2}Σ^{+}, ^{2}Π, ^{2}Δ | |

S^{2+}(3s^{2}3p^{2})^{3}P + He^{+}(1s)^{2}S | ^{2,4}Σ^{+},^{2,4}Π |

^{2+}(3s

^{2}3p

^{2})

^{3}P + He

^{+}(1s)

^{2}S corresponding to a very long range avoided crossing with the entry channel has not been taken into account. In that case, one-electron capture channels only have to be taken into account, effectively, the S

^{2+}(3s3p

^{3}) transfer-excitation levels corresponding to electron capture and excitation of a 3s electron cannot be reached in this process, with regard to the ionization potential of helium, higher than in hydrogen.

**Figure 7.**Adiabatic potential energy curves of SHe

^{3+};

^{2}Π states;

^{2}Σ states; Δ state in decreasing energy order : S

^{3+}(3s

^{2}3p)

^{2}P + He(1s

^{2})

^{1}S, entry channel; S

^{2+}(3s

^{2}3p

^{2})

^{1}S + He

^{+}(1s)

^{2}S; S

^{2+}(3s

^{2}3p

^{2})

^{1}D + He

^{+}(1s)

^{2}S; S

^{2+}(3s

^{2}3p

^{2})

^{3}P + He

^{+}(1s)

^{2}S.

^{3+}(3s

^{2}3p)

^{2}P + H case: as far as spin-orbit effects may be neglected in the collision energy range of interest, we have to consider four

^{2}Σ

^{+}, three

^{2}Π coupled respectively by radial coupling matrix elements, and one

^{2}Δ coupled by rotational coupling. The whole molecular results are presented and discussed in ref. [8]. We show here (Figure 7) only the potential energy curves in order to have an overview of the behaviour of this system. Two main avoided crossings can be observed: one between the entry channel and the

^{2}Σ

^{+}{S

^{2+}(3s

^{2}3p

^{2})

^{1}S + He

^{+}(1s)

^{2}S} level around R=8.0 a.u., and the most important one, around R=6.0 a.u., with the

^{2}Σ

^{+},

^{2}Π{S

^{2+}(3s

^{2}3p

^{2})

^{1}D + He

^{+}(1s)

^{2}S} exit channels. The interaction with the

^{2}Σ

^{+},

^{2}Π{S

^{2+}(3s

^{2}3p

^{2})

^{3}P + He

^{+}(1s)

^{2}S} levels presents a wider avoided crossing around R=5.5 a.u.

^{3+}(3s

^{2}3p)

^{2}P + H process. The main reactions corresponding to the experimental peaks A, B, C are in that case:

S^{3+}(3s^{2}3p)^{2}P + He(1s^{2})^{1}S → | S^{2+}(3s^{2}3p^{2})^{1}D + He^{+}(1s)^{2}S | peak A |

S^{3+}(3s^{2}3p)^{2}P + He(1s^{2})^{1}S → | S^{2+}(3s^{2}3p^{2})^{3}P + He^{+}(1s)^{2}S | peak B |

S^{3+}(3s^{2}3p)^{2}P + He(1s^{2})^{1}S → | S^{2+}(3s^{2}3p^{2})^{1}S + He^{+}(1s)^{2}S | peak C |

**Figure 8.**Partial cross sections on the S

^{3+}(3s

^{2}3p)

^{2}P + He levels with respect with laboratory energies. peak A ; peak B; peak C;${+++}$(experiment [6]) / (calculation), ratio σ

_{B}/σ

_{A}.

^{3+}(3s

^{2}3p)

^{2}P + H process where the peak A is the highest one.

## Concluding remarks

^{3+}(3s

^{2}3p)

^{2}P° + H/He collisional systems. Electron capture by 2-8 keV S

^{3+}(

^{2}P°) ground-state ions in H and He is dominated by capture of 3p electron, with further 3s to 3p excitation of the projectile ion in the case of the S

^{3+}(3s

^{2}3p)

^{2}P° + H process. A precise attribution of the experimental spectra is provided with a good agreement between experimental and theoretical approaches, in particular evidence of the existence of the {S

^{2+}(3s

^{2}3p3d)

^{3}F° + H

^{+1}S} capture channel associated to the main experimental peak A in the S

^{3+}(3s

^{2}3p)

^{2}P° + H process may be pointed out, in accordance with translational energy spectroscopy measurements [6].

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## Share and Cite

**MDPI and ACS Style**

Łabuda, M.; Tergiman, Y.S.; Bacchus-Montabonel, M.-C.; Sienkiewicz, J.E.
State Selective Electron Capture in the Collision of S^{3+} Ions in Atomic Hydrogen and Helium. *Int. J. Mol. Sci.* **2004**, *5*, 265-275.
https://doi.org/10.3390/i5110265

**AMA Style**

Łabuda M, Tergiman YS, Bacchus-Montabonel M-C, Sienkiewicz JE.
State Selective Electron Capture in the Collision of S^{3+} Ions in Atomic Hydrogen and Helium. *International Journal of Molecular Sciences*. 2004; 5(11):265-275.
https://doi.org/10.3390/i5110265

**Chicago/Turabian Style**

Łabuda, Marta, Y. Suzanne Tergiman, Marie-Christine Bacchus-Montabonel, and Jozef E. Sienkiewicz.
2004. "State Selective Electron Capture in the Collision of S^{3+} Ions in Atomic Hydrogen and Helium" *International Journal of Molecular Sciences* 5, no. 11: 265-275.
https://doi.org/10.3390/i5110265